RE: [xml-dev] Data versioning strategy: address semantic, relationship,

[Len Bullard <len.bullard@uai.com>]

CLARITY SOUGHT

>What does this mean: "The version management needs to be embedded in a
>business process"?

The question is, do the rules of the process subsume or disregard the rules
for all other processes that can consume that version.  You cannot place
constraints but you can produce a version that some consumer is not eligible
to consume.   In short, if you control distribution, you would have to know
all states of all consumers that can be affected by a version.   Otherwise
(and this is more practical), the consumer must know the conditions of all
local versions and the specific breakage points given a new version they
might receive.

If you are Microsoft and you distribute a patch, does your distribution
install check all versions on the local machine prior to installing the
patch?  To a certain level, yes.  That is what I mean when I say this is a
tools strategy (Where is the intelligence?  In the install script.)

>What does it mean: "Avoid placing constraints on consumers of the
>data"?

Actually, you can't.  They are eligible or ineligible to receive the update.
This will true in the case of data or semantically laden packages.  The
kinds of breakage will be different.

>Can we view an example of: "A semantically non-breaking change for one
>class of consumer might present problems for another"?

That's easy.  Try to download a version of media player for Vista to a Win
3.1 machine.  Try to merge 1899 census data into a 1998 database.

It isn't the class of the consumer.  It is the state of the consumer.  State
management is and always will be the devil of the web.  Yes, you can use
URIs to identify versions.  That is what you should do.   The problem is
that the XML can be anything it wants to be but the consuming database may
not have any slots for that data.  Now the question of business rules
pertains:  ignore, inform, store and forward?

len


 
This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the sender. This message contains confidential information and is intended only for the individual named. If you are not the named addressee you should not disseminate, distribute or copy this e-mail.